Acoustically damped component

Abstract

Acoustically damped component for a vehicle, an engine, a transmission or a vehicle trim panel, includes a flat basic body provided on at least one side with a rib structure. The ribs of the rib structure form chambers which are arranged irregularly on at least one region of the component, which has a resonant frequency of from 200 to 1000 Hz. The chambers are configured irregularly in such a way that chambers of the component have different dimensioning and / or geometry in comparison with adjoining chambers, such that emitted airborne sound can be reduced and / or eradicated. A response to a transient excitation of at least two part areas of that surface of the component which is provided with the chambers having a correlation of from 0.5 to 0.85, preferably of from 0.6 to 0.7.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an acoustically damped component preferably for a vehicle, an engine, a transmission or a vehicle trim panel comprising a flat basic body which is provided on at least one side at least in regions with a rib structure, the ribs of the rib structure forming chambers and the chambers being arranged irregularly on at least one region of the component.[0003]2. Description of the Related Art[0004]U.S. Pat. No. 3,773,141 teaches a wall element which is provided with a lattice structure and forms a highly rigid and greatly noise-damped component with a low additional material requirement. Here, the wall element is of particularly rigid construction as a result of the lattice structure, the ratio of rib height plus basic-body thickness to basic-body thickness being greater than 4 and, at the same time, the ratio of chamber inner-side length to the rib thickness is between 4 and 14. U.S. Pat. No....

AI Technical Summary

Benefits of technology

The patent text describes a new discovery that the ribs on a component can help reduce or eliminate sound emitted from the component. This is because the ribs create a barrier that prevents sound from being emitted in certain frequency bands. To achieve the desired sound pressure levels in these bands, the component needs to have a certain level of flexibility or resilience despite the rib system. The text also suggests that the component can be made from plastic or composite materials, like injection-molded parts, which allows for the complicated structure of the ribs to be realized in a cost-effective way.

Problems solved by technology

It has been discovered that the ribs can serve as delimitation of part areas which have an irregular structure and in the process, on account of the stochastic distribution of acoustic dipole sources, bring about mutual reduction or eradication of emitted airborne sound in the near field and therefore do not permit sound emission in a frequency band (band-stop filter).

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